/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package kim.spider.serializer.avro;

import java.util.HashSet;
import java.util.Set;

import org.apache.avro.AvroTypeException;
import org.apache.avro.Schema;
import org.apache.avro.io.DatumReader;
import org.apache.avro.io.DatumWriter;
import org.apache.avro.reflect.ReflectData;
import org.apache.avro.reflect.ReflectDatumReader;
import org.apache.avro.reflect.ReflectDatumWriter;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.serializer.avro.AvroReflectSerializable;
import org.apache.hadoop.io.serializer.avro.AvroSerialization;
import org.mortbay.log.Log;

/**
 * Serialization for Avro Reflect classes. For a class to be accepted by this
 * serialization, it must either be in the package list configured via
 * <code>avro.reflect.pkgs</code> or implement {@link AvroReflectSerializable}
 * interface.
 * 
 */
@SuppressWarnings("unchecked")
@InterfaceAudience.Public
@InterfaceStability.Evolving
public class AvroReflectSerialization extends AvroSerialization<Object> {

	/**
	 * Key to configure packages that contain classes to be serialized and
	 * deserialized using this class. Multiple packages can be specified using
	 * comma-separated list.
	 */
	@InterfaceAudience.Private
	public static final String	AVRO_REFLECT_PACKAGES	= "avro.reflect.pkgs";

	private Set<String>					packages;

	@InterfaceAudience.Private
	@Override
	public synchronized boolean accept(Class<?> c) {
		if (packages == null) {
			getPackages();
		}
		boolean bacept = false;
		try {
			Schema schema = getSchema(c);
			if(schema != null)
				bacept = true;
		} catch (AvroTypeException e) {
			bacept = false;
		}
		
		if(bacept)
			return true;
		return AvroReflectSerializable.class.isAssignableFrom(c)
				|| packages.contains(c.getPackage().getName());
	}

	private void getPackages() {
		String[] pkgList = getConf().getStrings(AVRO_REFLECT_PACKAGES);
		packages = new HashSet<String>();
		if (pkgList != null) {
			for (String pkg : pkgList) {
				packages.add(pkg.trim());
			}
		}
	}

	@InterfaceAudience.Private
	@Override
	public DatumReader getReader(Class<Object> clazz) {
		try {
			return new ReflectDatumReader(clazz);
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	@InterfaceAudience.Private
	@Override
	public Schema getSchema(Object t) {
		return ReflectData.get().getSchema(t.getClass());
	}

	@InterfaceAudience.Private
	@Override
	public DatumWriter getWriter(Class<Object> clazz) {
		return new ReflectDatumWriter();
	}

}
